dfir_lang/graph/
mod.rs

1//! Graph representation stages for DFIR graphs.
2
3use std::borrow::Cow;
4use std::hash::Hash;
5
6use proc_macro2::{Ident, Span, TokenStream};
7use quote::ToTokens;
8use serde::{Deserialize, Serialize};
9use syn::punctuated::Punctuated;
10use syn::spanned::Spanned;
11use syn::{Expr, ExprPath, GenericArgument, Token, Type};
12
13use self::ops::{OperatorConstraints, Persistence};
14use crate::diagnostic::{Diagnostic, Diagnostics, Level};
15use crate::parse::{DfirCode, IndexInt, Operator, PortIndex, Ported};
16use crate::pretty_span::PrettySpan;
17
18mod di_mul_graph;
19mod eliminate_extra_unions_tees;
20mod flat_graph_builder;
21mod flat_to_partitioned;
22mod graph_write;
23mod meta_graph;
24mod meta_graph_debugging;
25
26use std::fmt::Display;
27
28pub use di_mul_graph::DiMulGraph;
29pub use eliminate_extra_unions_tees::eliminate_extra_unions_tees;
30pub use flat_graph_builder::{FlatGraphBuilder, FlatGraphBuilderOutput};
31pub use flat_to_partitioned::partition_graph;
32pub use meta_graph::{DfirGraph, WriteConfig, WriteGraphType};
33
34pub use crate::graph_ids::{GraphEdgeId, GraphLoopId, GraphNodeId, GraphSubgraphId};
35
36pub mod graph_algorithms;
37pub mod ops;
38
39impl GraphSubgraphId {
40    /// Generate a deterministic `Ident` for the given subgraph ID.
41    pub fn as_ident(self, span: Span) -> Ident {
42        use slotmap::Key;
43        Ident::new(&format!("sgid_{:?}", self.data()), span)
44    }
45}
46
47impl GraphLoopId {
48    /// Generate a deterministic `Ident` for the given loop ID.
49    pub fn as_ident(self, span: Span) -> Ident {
50        use slotmap::Key;
51        Ident::new(&format!("loop_{:?}", self.data()), span)
52    }
53}
54
55/// Context identifier as a string.
56const CONTEXT: &str = "context";
57/// Runnable DFIR graph object identifier as a string.
58const GRAPH: &str = "df";
59
60const HANDOFF_NODE_STR: &str = "handoff";
61const SINGLETON_SLOT_NODE_STR: &str = "singleton";
62const MODULE_BOUNDARY_NODE_STR: &str = "module_boundary";
63
64mod serde_syn {
65    use serde::{Deserialize, Deserializer, Serializer};
66
67    pub fn serialize<S, T>(value: &T, serializer: S) -> Result<S::Ok, S::Error>
68    where
69        S: Serializer,
70        T: quote::ToTokens,
71    {
72        serializer.serialize_str(&value.to_token_stream().to_string())
73    }
74
75    pub fn deserialize<'de, D, T>(deserializer: D) -> Result<T, D::Error>
76    where
77        D: Deserializer<'de>,
78        T: syn::parse::Parse,
79    {
80        let s = String::deserialize(deserializer)?;
81        syn::parse_str(&s).map_err(<D::Error as serde::de::Error>::custom)
82    }
83}
84
85/// A variable name assigned to a pipeline in DFIR syntax.
86///
87/// Fundamentally a serializable/deserializable wrapper around [`syn::Ident`].
88#[derive(Clone, Debug, Serialize, Deserialize, PartialOrd, Ord, PartialEq, Eq, Hash)]
89pub struct Varname(#[serde(with = "serde_syn")] pub Ident);
90
91/// The kind of inter-subgraph handoff.
92#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
93pub enum HandoffKind {
94    /// A `Vec<T>` buffer for streams (zero or more items).
95    Vec,
96    /// An `Option<T>` slot for singletons/optionals (zero or one item).
97    Option,
98}
99
100/// A node, corresponding to an operator or a handoff.
101#[derive(Clone, Serialize, Deserialize)]
102pub enum GraphNode {
103    /// An operator.
104    Operator(#[serde(with = "serde_syn")] Operator),
105    /// An inter-subgraph handoff point for buffering data between subgraphs.
106    Handoff {
107        /// What kind of storage this handoff uses.
108        kind: HandoffKind,
109        /// The span of the input into the handoff.
110        #[serde(skip, default = "Span::call_site")]
111        src_span: Span,
112        /// The span of the output out of the handoff.
113        #[serde(skip, default = "Span::call_site")]
114        dst_span: Span,
115    },
116
117    /// Module Boundary, used for importing modules. Only exists prior to partitioning.
118    ModuleBoundary {
119        /// If this module is an input or output boundary.
120        input: bool,
121
122        /// The span of the import!() expression that imported this module.
123        /// The value of this span when the ModuleBoundary node is still inside the module is Span::call_site()
124        /// TODO: This could one day reference into the module file itself?
125        #[serde(skip, default = "Span::call_site")]
126        import_expr: Span,
127    },
128}
129impl GraphNode {
130    /// Return the node as a human-readable string.
131    pub fn to_pretty_string(&self) -> Cow<'static, str> {
132        match self {
133            GraphNode::Operator(op) => op.to_pretty_string().into(),
134            GraphNode::Handoff {
135                kind: HandoffKind::Vec,
136                ..
137            } => HANDOFF_NODE_STR.into(),
138            GraphNode::Handoff {
139                kind: HandoffKind::Option,
140                ..
141            } => SINGLETON_SLOT_NODE_STR.into(),
142            GraphNode::ModuleBoundary { .. } => MODULE_BOUNDARY_NODE_STR.into(),
143        }
144    }
145
146    /// Return the name of the node as a string, excluding parenthesis and op source code.
147    pub fn to_name_string(&self) -> Cow<'static, str> {
148        match self {
149            GraphNode::Operator(op) => op.name_string().into(),
150            GraphNode::Handoff {
151                kind: HandoffKind::Vec,
152                ..
153            } => HANDOFF_NODE_STR.into(),
154            GraphNode::Handoff {
155                kind: HandoffKind::Option,
156                ..
157            } => SINGLETON_SLOT_NODE_STR.into(),
158            GraphNode::ModuleBoundary { .. } => MODULE_BOUNDARY_NODE_STR.into(),
159        }
160    }
161
162    /// Return the source code span of the node.
163    pub fn span(&self) -> Span {
164        match self {
165            Self::Operator(op) => op.span(),
166            &Self::Handoff {
167                src_span, dst_span, ..
168            } => src_span.join(dst_span).unwrap_or(src_span),
169            Self::ModuleBoundary { import_expr, .. } => *import_expr,
170        }
171    }
172}
173impl std::fmt::Debug for GraphNode {
174    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
175        match self {
176            Self::Operator(operator) => {
177                write!(f, "Node::Operator({} span)", PrettySpan(operator.span()))
178            }
179            Self::Handoff { kind, .. } => write!(f, "Node::Handoff({kind:?})"),
180            Self::ModuleBoundary { input, .. } => {
181                write!(f, "Node::ModuleBoundary{{input: {}}}", input)
182            }
183        }
184    }
185}
186
187/// Meta-data relating to operators which may be useful throughout the compilation process.
188///
189/// This data can be generated from the graph, but it is useful to have it readily available
190/// pre-computed as many algorithms use the same info. Stuff like port names, arguments, and the
191/// [`OperatorConstraints`] for the operator.
192///
193/// Because it is derived from the graph itself, there can be "cache invalidation"-esque issues
194/// if this data is not kept in sync with the graph.
195#[derive(Clone, Debug)]
196pub struct OperatorInstance {
197    /// Name of the operator (will match [`OperatorConstraints::name`]).
198    pub op_constraints: &'static OperatorConstraints,
199    /// Port values used as this operator's input.
200    pub input_ports: Vec<PortIndexValue>,
201    /// Port values used as this operator's output.
202    pub output_ports: Vec<PortIndexValue>,
203    /// Singleton references within the operator arguments.
204    pub singletons_referenced: Vec<Ident>,
205
206    /// Generic arguments.
207    pub generics: OpInstGenerics,
208    /// Arguments provided by the user into the operator as arguments.
209    /// I.e. the `a, b, c` in `-> my_op(a, b, c) -> `.
210    ///
211    /// These arguments do not include singleton postprocessing codegen. Instead use
212    /// [`ops::WriteContextArgs::arguments`].
213    pub arguments_pre: Punctuated<Expr, Token![,]>,
214    /// Unparsed arguments, for singleton parsing.
215    pub arguments_raw: TokenStream,
216}
217
218/// Operator generic arguments, split into specific categories.
219#[derive(Clone, Debug)]
220pub struct OpInstGenerics {
221    /// Operator generic (type or lifetime) arguments.
222    pub generic_args: Option<Punctuated<GenericArgument, Token![,]>>,
223    /// Lifetime persistence arguments. Corresponds to a prefix of [`Self::generic_args`].
224    pub persistence_args: Vec<Persistence>,
225    /// Type persistence arguments. Corersponds to a (suffix) of [`Self::generic_args`].
226    pub type_args: Vec<Type>,
227}
228
229impl OpInstGenerics {
230    /// Helper to join a sequence of spans into a single span, if possible.
231    ///
232    /// Returns `None` if there are no spans or if any `Span::join` call fails
233    /// (for example, when spans are not contiguous).
234    fn join_spans<I>(mut spans: I) -> Option<Span>
235    where
236        I: Iterator<Item = Span>,
237    {
238        let mut span = spans.next()?;
239        for s in spans {
240            span = span.join(s)?;
241        }
242        Some(span)
243    }
244
245    /// Returns a [`Span`] containing all persistence (lifetime) args if possible.
246    pub fn persistence_args_span(&self) -> Option<Span> {
247        self.generic_args.as_ref().and_then(|args| {
248            Self::join_spans(
249                args.iter()
250                    .filter(|a| matches!(a, GenericArgument::Lifetime(_)))
251                    .map(|a| a.span()),
252            )
253        })
254    }
255
256    /// Returns a [`Span`] containing all type args if possible.
257    pub fn type_args_span(&self) -> Option<Span> {
258        self.generic_args.as_ref().and_then(|args| {
259            Self::join_spans(
260                args.iter()
261                    .filter(|a| matches!(a, GenericArgument::Type(_)))
262                    .map(|a| a.span()),
263            )
264        })
265    }
266}
267
268/// Gets the generic arguments for the operator.
269///
270/// This helper method is useful due to the special handling of persistence lifetimes (`'static`,
271/// `'tick`, `'mutable`) which must come before other generic parameters.
272pub fn get_operator_generics(diagnostics: &mut Diagnostics, operator: &Operator) -> OpInstGenerics {
273    // Generic arguments.
274    let generic_args = operator.type_arguments().cloned();
275    let persistence_args = generic_args.iter().flatten().map_while(|generic_arg| match generic_arg {
276            GenericArgument::Lifetime(lifetime) => {
277                match &*lifetime.ident.to_string() {
278                    "none" => Some(Persistence::None),
279                    "loop" => Some(Persistence::Loop),
280                    "tick" => Some(Persistence::Tick),
281                    "static" => Some(Persistence::Static),
282                    "mutable" => Some(Persistence::Mutable),
283                    _ => {
284                        diagnostics.push(Diagnostic::spanned(
285                            generic_arg.span(),
286                            Level::Error,
287                            format!("Unknown lifetime generic argument `'{}`, expected `'none`, `'loop`, `'tick`, `'static`, or `'mutable`.", lifetime.ident),
288                        ));
289                        // TODO(mingwei): should really keep going and not short circuit?
290                        None
291                    }
292                }
293            },
294            _ => None,
295        }).collect::<Vec<_>>();
296    let type_args = generic_args
297        .iter()
298        .flatten()
299        .skip(persistence_args.len())
300        .map_while(|generic_arg| match generic_arg {
301            GenericArgument::Type(typ) => Some(typ),
302            _ => None,
303        })
304        .cloned()
305        .collect::<Vec<_>>();
306
307    OpInstGenerics {
308        generic_args,
309        persistence_args,
310        type_args,
311    }
312}
313
314/// Push, Pull, Comp, or Hoff polarity.
315#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
316pub enum Color {
317    /// Pull (green)
318    Pull,
319    /// Push (blue)
320    Push,
321    /// Computation (yellow)
322    Comp,
323    /// Handoff (grey) -- not a color for operators, inserted between subgraphs.
324    Hoff,
325}
326
327/// Helper struct for [`PortIndex`] which keeps span information for elided ports.
328#[derive(Clone, Debug, Serialize, Deserialize)]
329pub enum PortIndexValue {
330    /// An integer value: `[0]`, `[1]`, etc. Can be negative although we don't use that (2023-08-16).
331    Int(#[serde(with = "serde_syn")] IndexInt),
332    /// A name or path. `[pos]`, `[neg]`, etc. Can use `::` separators but we don't use that (2023-08-16).
333    Path(#[serde(with = "serde_syn")] ExprPath),
334    /// Elided, unspecified port. We have this variant, rather than wrapping in `Option`, in order
335    /// to preserve the `Span` information.
336    Elided(#[serde(skip)] Option<Span>),
337}
338impl PortIndexValue {
339    /// For a [`Ported`] value like `[port_in]name[port_out]`, get the `port_in` and `port_out` as
340    /// [`PortIndexValue`]s.
341    pub fn from_ported<Inner>(ported: Ported<Inner>) -> (Self, Inner, Self)
342    where
343        Inner: Spanned,
344    {
345        let ported_span = Some(ported.inner.span());
346        let port_inn = ported
347            .inn
348            .map(|idx| idx.index.into())
349            .unwrap_or_else(|| Self::Elided(ported_span));
350        let inner = ported.inner;
351        let port_out = ported
352            .out
353            .map(|idx| idx.index.into())
354            .unwrap_or_else(|| Self::Elided(ported_span));
355        (port_inn, inner, port_out)
356    }
357
358    /// Returns `true` if `self` is not [`PortIndexValue::Elided`].
359    pub fn is_specified(&self) -> bool {
360        !matches!(self, Self::Elided(_))
361    }
362
363    /// Returns whichever of the two ports are specified.
364    /// If both are [`Self::Elided`], returns [`Self::Elided`].
365    /// If both are specified, returns `Err(self)`.
366    #[allow(clippy::allow_attributes, reason = "Only triggered on nightly.")]
367    #[allow(
368        clippy::result_large_err,
369        reason = "variants are same size, error isn't to be propagated."
370    )]
371    pub fn combine(self, other: Self) -> Result<Self, Self> {
372        match (self.is_specified(), other.is_specified()) {
373            (false, _other) => Ok(other),
374            (true, false) => Ok(self),
375            (true, true) => Err(self),
376        }
377    }
378
379    /// Formats self as a human-readable string for error messages.
380    pub fn as_error_message_string(&self) -> String {
381        match self {
382            PortIndexValue::Int(n) => format!("`{}`", n.value),
383            PortIndexValue::Path(path) => format!("`{}`", path.to_token_stream()),
384            PortIndexValue::Elided(_) => "<elided>".to_owned(),
385        }
386    }
387
388    /// Returns the span of this port value.
389    pub fn span(&self) -> Span {
390        match self {
391            PortIndexValue::Int(x) => x.span(),
392            PortIndexValue::Path(x) => x.span(),
393            PortIndexValue::Elided(span) => span.unwrap_or_else(Span::call_site),
394        }
395    }
396}
397impl From<PortIndex> for PortIndexValue {
398    fn from(value: PortIndex) -> Self {
399        match value {
400            PortIndex::Int(x) => Self::Int(x),
401            PortIndex::Path(x) => Self::Path(x),
402        }
403    }
404}
405impl PartialEq for PortIndexValue {
406    fn eq(&self, other: &Self) -> bool {
407        match (self, other) {
408            (Self::Int(l0), Self::Int(r0)) => l0 == r0,
409            (Self::Path(l0), Self::Path(r0)) => l0 == r0,
410            (Self::Elided(_), Self::Elided(_)) => true,
411            _else => false,
412        }
413    }
414}
415impl Eq for PortIndexValue {}
416impl PartialOrd for PortIndexValue {
417    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
418        Some(self.cmp(other))
419    }
420}
421impl Ord for PortIndexValue {
422    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
423        match (self, other) {
424            (Self::Int(s), Self::Int(o)) => s.cmp(o),
425            (Self::Path(s), Self::Path(o)) => s
426                .to_token_stream()
427                .to_string()
428                .cmp(&o.to_token_stream().to_string()),
429            (Self::Elided(_), Self::Elided(_)) => std::cmp::Ordering::Equal,
430            (Self::Int(_), Self::Path(_)) => std::cmp::Ordering::Less,
431            (Self::Path(_), Self::Int(_)) => std::cmp::Ordering::Greater,
432            (_, Self::Elided(_)) => std::cmp::Ordering::Less,
433            (Self::Elided(_), _) => std::cmp::Ordering::Greater,
434        }
435    }
436}
437
438impl Display for PortIndexValue {
439    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
440        match self {
441            PortIndexValue::Int(x) => write!(f, "{}", x.to_token_stream()),
442            PortIndexValue::Path(x) => write!(f, "{}", x.to_token_stream()),
443            PortIndexValue::Elided(_) => write!(f, "[]"),
444        }
445    }
446}
447
448/// Output of [`build_dfir_code`].
449pub struct BuildDfirCodeOutput {
450    /// The now-partitioned graph.
451    pub partitioned_graph: DfirGraph,
452    /// The Rust source code tokens for the DFIR.
453    pub code: TokenStream,
454    /// Any (non-error) diagnostics emitted.
455    pub diagnostics: Diagnostics,
456}
457
458/// Compiles a [`DfirCode`] AST into inline source code that runs the dataflow.
459pub fn build_dfir_code(
460    dfir_code: DfirCode,
461    root: &TokenStream,
462) -> Result<BuildDfirCodeOutput, Diagnostics> {
463    let flat_graph_builder = FlatGraphBuilder::from_dfir(dfir_code);
464
465    let FlatGraphBuilderOutput {
466        mut flat_graph,
467        uses,
468        mut diagnostics,
469    } = flat_graph_builder.build()?;
470
471    let () = match flat_graph.merge_modules() {
472        Ok(()) => (),
473        Err(d) => {
474            diagnostics.push(d);
475            return Err(diagnostics);
476        }
477    };
478
479    eliminate_extra_unions_tees(&mut flat_graph);
480
481    // Reject `loop { }` blocks (not yet supported in inline codegen).
482    // TODO(cleanup): find a better home for this check — ideally inside `partition_graph` once
483    // it supports returning multiple diagnostics.
484    for (_loop_id, nodes) in flat_graph.loops() {
485        let span = nodes
486            .first()
487            .map_or_else(Span::call_site, |&n| flat_graph.node(n).span());
488        diagnostics.push(Diagnostic::spanned(
489            span,
490            Level::Error,
491            "`loop { }` blocks are not (yet) supported in `dfir_syntax!`.",
492        ));
493    }
494    if diagnostics.has_error() {
495        return Err(diagnostics);
496    }
497
498    let partitioned_graph = match partition_graph(flat_graph) {
499        Ok(partitioned_graph) => partitioned_graph,
500        Err(d) => {
501            diagnostics.push(d);
502            return Err(diagnostics);
503        }
504    };
505
506    let code =
507        partitioned_graph.as_code(root, true, quote::quote! { #( #uses )* }, &mut diagnostics)?;
508
509    Ok(BuildDfirCodeOutput {
510        partitioned_graph,
511        code,
512        diagnostics,
513    })
514}
515
516/// Changes all of token's spans to `span`, recursing into groups.
517fn change_spans(tokens: TokenStream, span: Span) -> TokenStream {
518    use proc_macro2::{Group, TokenTree};
519    tokens
520        .into_iter()
521        .map(|token| match token {
522            TokenTree::Group(mut group) => {
523                group.set_span(span);
524                TokenTree::Group(Group::new(
525                    group.delimiter(),
526                    change_spans(group.stream(), span),
527                ))
528            }
529            TokenTree::Ident(mut ident) => {
530                ident.set_span(span.resolved_at(ident.span()));
531                TokenTree::Ident(ident)
532            }
533            TokenTree::Punct(mut punct) => {
534                punct.set_span(span);
535                TokenTree::Punct(punct)
536            }
537            TokenTree::Literal(mut literal) => {
538                literal.set_span(span);
539                TokenTree::Literal(literal)
540            }
541        })
542        .collect()
543}
dfir_lang/graph/mod.rs

dfir_lang/graph/
mod.rs
